Stop frost!

Compiled by Anne-Laure Herbet, 2002

Ever since the 1950s the Champagne Houses have been experimenting with different methods of frost protection — some more effective than others, all of them highly ingenious. Those still used in the vineyards today are reviewed below by three Champagne Winegrowers with a real love for their job.

Frost protection specialist Olivier Brun looks back at early methods of frost protection introduced at the end of the 19th Century. It was the 1950s before the Champagne region began tackling the problem in earnest, at a time when frost damage had reached epic proportions. These were the years when frost could wipe out (brûler in French) entire blocks of fruit (as in 1951 when the average yield per hectare was just 2,900kg). The Champagne region was meanwhile enjoying an economic boom that saw a sharp rise in exports.

As Champagne Houses and Growers fought to save their crop, Mumm invested heavily in cutting-edge research into frost protection technology. So began a period of intensive experimentation that would continue for the next two decades. In the Avize vineyards for instance, winegrowers even went so far as to measure the temperature inside the buds — proving that for people who love their vines, no price is too great to pay for progress.

A good many of the techniques tried and tested at the time proved to be effective, positioning Mumm at the forefront of research in the area of frost protection. By 1972 the House was ready to launch the ’Haltogel’ frost protection method: an automated filling and lighting system that significantly increased the effectiveness of smudge pots (chaufferettes), triggered when the temperature dropped to dangerous levels (especially at night). A pulverized fuel firing system meanwhile greatly increased the amount of heat released. For Olivier Brun the spirit of innovation that drove the House of Mumm reinforced his resolve to take the technology to another level.

... sprinkler irrigation

Mumm now recommends using sprinkler irrigation as an approved alternative to smudge pots. Here, the buds are sprayed continuously in sub-zero temperatures (using sprinklers spaced 15-20m apart) to prevent the nascent crop itself from freezing. It works on the basis that melting ice is above freezing.

Sprinkler irrigation proved its worth in 1967, in Chambrecy, saving the only hectare to emerge unscathed from the severe frost that hit the entire length of Champagne’s vineyards. The principal difficulty resides in the water supply: it takes 50m3 per hectare to keep the buds wet, not just damp or they will surely freeze. The efficacy of both systems is now well established, serving to protect all of the plots that were undamaged by frost in 1991 — to give but one example. Mumm now relies exclusively on sprinkler irrigation but only in high risk areas. These days temperatures rarely drop below zero and Champagne yields are no longer what they were. Despite those severe frosts of 1991, the average yield per hectare back then was still 11,500 kg.

Bricout-Delbeck: from sprinklers to ...
When Pierre Martin, of Champagne House Bricout & Delbeck, talks about his vines it is like listening to a father talk about his children — the same loving attention, the same affection, you might say. Part of the vineyard is located in the Côte des Bar, one of the most frost-prone areas in the whole of Champagne.

It was to protect his tender buds from frost damage that PIerre Martin declared war on frost all those years ago. Frost was his worst enemy — it put paid to any hope of a decent harvest, sometimes wiping out the entire crop, and it also accelerated vine aging.

So in 1966 Pierre Martin installed smudge pots in the heart of his vineyard in Bouzy, which he gradually modernised by introducing one main fuel feed line that supplied each of the smudge pots in turn. Each smudge pot was equipped with a float-regulated fuel tank plus an electrically operated (dynamo powered) igniter for lighting the fuel in the tank.

Les vignes Bricout parées de guirlandes de glace

The stakes were high enough to justify the installation of a back up sprinkler irrigation system. Once in place, the two systems depended on the constant monitoring of the moisture content in the air. Accurate weather forecasting was particularly important in the case of sprinkler irrigation, which required a massive supply of water. Any interruption in sprinkling while the frost lasted would have been catastrophic. It was thanks to this dual system of frost protection that the House was able to save its crops in 1971 and 1991 — other producers were not so lucky.

... a constant watchfulness
After 22 years of fighting a relentless battle against frost, Pierre Martin no longer sees things in black and white. He has learned to live with his natural enemy and questions the economic sense of trying to overcome frost. The picture has changed and the House has suspended its frost protection activities.

The thinking has moved on, driven more by common sense than any desire to take the easy way out. The last time frost wiped out 100% of the crop was in 1957, across three consecutive nights when the temperature dipped to less than nine degrees Celsius, which is exceptional for Champagne. Severe frosts are increasingly rare these days, not just because of global warming but also due to the reduction of fallow land (where the soils are typically colder and more prone to frost than cropped lands).

As authorized production yields have increased, it has also become possible to set aside part of the harvest to cushion the effects of a future frost-damaged vintage. Vine selection is another factor that makes frost protection much less critical than it was. Today’s carefully selected plantings are better able to recover from frost damage than their predecessors (producing secondary buds with considerably more fruit). Then there are the costs to consider — whether the potential losses incurred by frost damage justify outlay on the installation and maintenance of a frost protection system. So all things considered, Pierre Martin now does without frost protection in his vineyard — having had the satisfaction of saving his vines in those years when he had no other choice. And he stands ready to do it again should the need arise.

Moët & Chandon valiant struggle...
Michel Saunier is vineyard manager of Moët & Chandon’s Montagne de Reims holding. He has been fighting frost tooth and nail since he first got here, and there is nothing he likes better than to talk of his battle with the arch-enemy. Here he reviews some of the tools that were placed at his disposal by Moët & Chandon — the biggest Champagne House in the world, with ever-more elaborate frost protection methods to match.

The House’s frost protection campaign kicked off in the early 1960s with the installation of 50-litre smudge pots, followed by Brenntag pulverized fuel burners. The 1973 oil crisis then saw a move to gas, partly because the cost of petrol had become prohibitive and partly because of the air pollution generated by those hundreds of black-smoke-belching smudge pots. So for the next ten years (until they proved too dangerous and had to be abandoned) the vineyards relied on gas-powered burners, which connected via a system of tubes to a gas cylinder (butane) positioned at the edge of the vineyard.

Moet & Chandon’s preferred method of frost protection is now sprinkler irrigation, with the sprinklers arranged in staggered rows to avoid the risk of holes. Wells are employed to overcome any water-supply problem.

... continues to this day
Sprinkler irrigation is now the only system used by Moët & Chandon, protecting some 50-55 hectares of vital plantings where frost damage would do irrevocable harm. Since all of the House’s vineyards are equally frost-prone, Michel Saunier is convinced that the fight must go on.

Un ballet aquatique protège les vignes Moët

In 2001, the year of this article, sprinkler irrigation was only required on two nights, when the temperature dipped below 4.5 degrees Celsius. In 1977 by comparison it was required for six nights in a row. The method was chosen because it works out cheaper in the long run despite the high initial capital outlay. It also uses readily available water, which does no harm to the environment. But wonderful as it may seem, sprinkler irrigation remains very unreliable. The sprinklers can break down or suddenly dry up, condemning the dripping buds to a freezing death. Soil erosion is another problem that must be constantly monitored, particularly in impermeable soils where run-off water can form gullies.

Michel Saunier speaks from experience when he says that the decision to install frost protection is never taken lightly. The moisture content in the air, wind, soil humidity and the stage of development of the vine buds are all factors that have to be considered in the space of a few minutes — which is also all the time it takes for frost to wipe out an entire crop.